The effectiveness of water mist fire protection systems for protection against industrial hazards has historically been evaluated by conducting full-scale fire tests in which a full size mock-up of a commodity is arranged as it would normally be found in industry. Although the fire protection industry still relies primarily on the full-scale fire testing approach to develop water mist fire protection systems, this approach drives up the cost and, thus, makes many potential applications economically prohibitive to develop. As a result, it is desirable to find a cost-effective testing method to evaluate the performance of water mist systems.
To replicate full-scale fire suppression phenomena with a geometrically similar scaled-down model, water mist sprays are used in a model simulation according to prescribed relationships with the scale ratio for drop size, total water mist discharge rate, mist flux and mist concentration. To ensure that appropriate water mist sprays that make the modeling valid are used, a two-dimensional Phase Doppler Particle Analyzer (PDPA) is used to screen candidate nozzles for use in the scaled-down model.